The present invention pertains generally to the field of grizzly feeders used in mining and construction industries. Grizzly feeders act as separators or filters and aid in the process of separating large rock from fine material. More particularly this invention relates to the construction of the separating elements within grizzly feeders known as “grizzly screen members.”
As indicated in U.S. Pat. No. 3,261,108A, a grizzly feeder is a device having a deck or panel of longitudinally spaced inclined bars (“grizzly screen members”) used in the mining and construction industries for separating relatively large size particles of material from particles of smaller sizes. A grizzly feeder is used for high volume scalping of aggregates, ores, coal etc., ahead of crushers, washers or similar equipment. Grizzly screen members are traditionally welded onto a panel or frame within a grizzly feeder.
The prior art teaches that the particles, as mentioned above, are fed onto a vibrating grizzly feeder and begin to traverse down the inclined grizzly screen members via the gravity and the vibration force. Particles smaller than the longitudinal space between two grizzly screen members fall between the grizzly screen members and are sifted out, while particles that are larger than the longitudinal space do not fall between the grizzly screen members and traverse all the way down the bars to the crusher.
For various grizzly feeder applications, grizzly screen members themselves have been designed with different shapes, sizes, and materials such as cast Manganese, alloyed steel, and chromium carbide. The prior art has discloses grizzly screen members with a proximal and distal end, the proximal end being welded at the top of the incline, while the distal end is that the base of the incline. Typically the overall width of the grizzly screen members taper from a wider proximal end to a narrower distal end. The prior art has also discloses grizzly screen members with a T-Shaped, triangular, trapezoidal, pentagonal, and other inventive polygonal cross-sections all designed for specific mining and crushing operations.
Grizzly screen members are considered consumable items which wear out from the abrasion and impact of the particles traversing down the panels. Despite the particular material and cross-sectional designs of individual grizzly screen members, due to the nature of the operation of the grizzly feeder and the way particles traverse down the panels and into the crushers, grizzly screen members typically wear down and or fail resulting in the need for repair or replacement. The distal end or discharge end, which can vary in length, but in some instances is the last 18-24 inches of each grizzly screen member, depending upon the size and style of grizzly, receives the most wear and fails sooner than the other sections of the grizzly screen member. When the grizzly screen members wear down in size, the filtered material is not properly sized, thus resulting in loss of production.
Replacement or repairs of a single grizzly screen member or panel is costly and labor intensive. Repairs are typically performed by manual weld buildup of the worn-out ends of individual grizzly screen members, while replacement involves removing and replacing individual screen members or entire panels. Both replacement and repair can result in significant down time of the grizzly feeder leading to significant downtime in the mining operation in general. The present invention addresses both of these shortcomings of the current prior art grizzly screen member variations.